Housing and method for making the same

ABSTRACT

A housing is provided which includes an aluminum or aluminum alloys substrate, an aluminum layer and a corrosion resistant layer formed on the aluminum or aluminum alloys substrate in that order. The corrosion resistant layer is an Al—O—N layer. Then, La ions is implanted in the Al—O—N layer by ion implantation process. The atomic percentages of N and O in the Al—O—N gradient layer gradually increase from the bottom of the layer near the aluminum or aluminum alloys substrate to the top of the layer away from aluminum or aluminum alloys substrate by physical vapor deposition. The housing has a higher corrosion resistance. A method for making the housing is also provided.

This application is related to co-pending U.S. patent application Ser.Nos. 13/191,609, 13/191,602, entitled “HOUSING AND METHOD FOR MAKING THESAME”. Such applications have the same assignee as the presentapplication. The above-identified applications are incorporated hereinby reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a housing and a method for making thesame.

2. Description of Related Art

Due to properties such as light weight and quick heat dissipation,aluminum and aluminum alloys are widely used in manufacturing components(such as housings) of electronic devices. Aluminum and aluminum alloysare usually anodized to form an oxide coating thereon to achieve adecorative and wear resistant surface. However, the anodizing process iscomplicated and not very effective.

Therefore, there is room for improvement within the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiments can be better understood with referenceto the following drawings. The components in the drawings are notnecessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the exemplary process for surfacetreating aluminum or aluminum alloys and housings made of aluminum oraluminum alloys treated by the surface treatment. Moreover, in thedrawings like reference numerals designate corresponding partsthroughout the several views. Wherever possible, the same referencenumbers are used throughout the drawings to refer to the same or likeelements of an embodiment.

FIG. 1 illustrates a cross-sectional view of an exemplary embodiment ofa housing made of aluminum or aluminum alloys treated by presentprocess.

FIG. 2 is a block diagram of an exemplary process for surface treatingaluminum or aluminum alloys

FIG. 3 is a schematic view of a PVD machine used in the present process.

FIG. 4 is a schematic view of an ion implantation machine used in thepresent process.

DETAILED DESCRIPTION

FIG. 1 shows a device housing 10 according to an exemplary embodiment.The device housing 10 includes an aluminum or aluminum alloys substrate11 having an aluminum layer 13 and a corrosion resistant layer 15 formedthereon and in that order.

The aluminum or aluminum alloys substrate 11 may be produced bypunching. The corrosion resistant layer 15 is an Al—O—N gradient layerdoped with La ions implanted by the ion implantation process. The atomicpercentages of N and O in the Al—O—N gradient Layer gradually increasefrom the bottom of the layer near the aluminum or aluminum alloyssubstrate to the top of the layer away from aluminum or aluminum alloyssubstrate.

FIG. 3 shows a vacuum sputtering equipment 20, which includes a vacuumchamber 21 and a vacuum pump 30 connected to the vacuum chamber 21. Thevacuum pump 30 is used for evacuating the vacuum chamber 21. The vacuumchamber 21 has a number of aluminum targets 23 and a rotary rack (notshown) positioned therein. The rotary rack drives the aluminum oraluminum alloy substrate 11 to rotate along a circular path 25, and thesubstrate 11 also rotates on its own axis while rotating along thecircular path 25.

FIG. 2 shows an exemplary method for making the device housing 10, whichmay include the following steps:

The aluminum or aluminum alloys substrate 11 is pretreated. Thepre-treating process may include the following steps:

The aluminum or aluminum alloys substrate 11 is cleaned with alcoholsolution in an ultrasonic cleaner (not shown), to remove impurities suchas grease or dirt from the aluminum or aluminum alloys substrate 11.Then, the substrate 11 is dried.

The aluminum or aluminum alloys substrate 11 is plasma cleaned. Thealuminum or aluminum alloys substrate 11 is positioned in the rotaryrack of the vacuum chamber 21. The vacuum chamber 21 is then evacuatedto about 3.0×10⁻⁸ Pa. Argon gas (abbreviated as Ar gas having a purityof about 99.999%) is used as sputtering gas and fed into the vacuumchamber 21 at a flow rate of about 500 standard-state cubic centimetersper minute (sccm). The aluminum or aluminum alloys substrate 11 isapplied with a negative bias voltage in a range of about −100 volts (V)to about −180 V, then high-frequency voltage is produced in the vacuumchamber 21 and the Ar gas is ionized into plasma. The plasma strikes thesurface of the aluminum or aluminum alloys substrate 11 to clean thesurface of the aluminum or aluminum alloys substrate 11. The plasmacleaning of the aluminum or aluminum alloys substrate 11 lasts about 3minutes (min) to about 10 min.

The aluminum layer 13 is vacuum sputtered on the pretreated an aluminumor aluminum substrate 11. In one exemplary embodiment, an aluminum layer13 is then formed on the aluminum or aluminum alloys substrate 11 byphysical vapor deposition (PVD). The formation of the aluminum layer 13uses argon gas as the sputtering gas. The flux of the argon is fromabout 100 sccm to about 300 sccm. During sputtering, the power of thealuminum targets is in a range of about 2 kw to about 8 kw, and thealuminum or aluminum substrate 11 is applied with a negative biasvoltage in a range of about −300 V to about −500 V. The vacuumsputtering to the aluminum layer takes about 5 min to about 10 min. Thealuminum layer 13 has a thickness in a range of about 100 nm to about300 nm.

The corrosion resistant layer 15 is formed on the aluminum layer 13. Thecorrosion resistant layer 15 is an Al—O—N gradient layer formed bymagnetron sputtering, and then the Al—O—N gradient layer is doped withLa ions by the ion implantation process. An exemplary magnetronsputtering process for forming the corrosion resistant layer 15 includesthe following steps: at first simultaneously applying argon, oxygen, andnitrogen, the flux of the argon being from about 100 sccm to about 300sccm, the flux of the oxygen is from about 10 sccm to about 20 sccm andthe flux of the nitrogen is from about 10 sccm to about 20 sccm;applying a bias voltage to the substrate in a range of about −150 V toabout −500 V. During this process, the flux of the nitrogen and oxygenflow rates are both increased approximately about 10 sccm to about 20sccm at depositing interval of about every 10 minutes to about 15minutes. The evaporation of the corrosion resistant layer 15 takes atotal time of about 30 min to about 90 min. The corrosion resistantlayer 15 has a thickness in a range of about 0.5 μm-about 2.0 μm.

The formation process of the corrosion resistant layer 15 may form adense Al—O—N solid phase, thus improving the density of the corrosionresistant layer 15. Therefore, corrosion resistance of the devicehousing 10 can be improved.

The atomic percentages of N and O in the corrosion resistant layer 15gradually increase from the bottom of the layer near the aluminum oraluminum alloys substrate 11 to the top of the layer away from thealuminum or aluminum alloys substrate, which can decrease themismatching of crystal lattices between the corrosion resistant layer 15and aluminum layer 13. The formation of the aluminum layer 13 betweenthe aluminum or aluminum alloy substrate 11 and the corrosion resistantlayer 15 may improve the interface mismatch between the aluminum oraluminum alloys substrate 11 and the corrosion resistant layer 15, andcan decrease the residual stress of the corrosion resistant layer 15.Thus the device housing 10 becomes less prone to stress corrosion. Thestress corrosion refers to the metal invalidity phenomenon under actionof residual or applied stress and corrosive medium. The device housing10 has a high corrosion resistance.

Lastly, the corrosion resistant layer 15 is implanted with La ion. Theimplanted ions can fill pores of the corrosion resistant layer 15 toimprove the density of the corrosion resistant layer 15. Furthermore,the corrosion resistant layer 15 is a homogeneous amorphous film. Thus,the corrosion resistance of the aluminum or aluminum alloys substrate 11can be improved.

La is implanted in the corrosion resistant layer 15 by ion implantationprocess. In an exemplary embodiment, the ion implantation process isperformed by supplying a process gas into a processing chamber 20 of anion implantation machine 100 as shown in FIG. 4. The machine 100includes a plasma source 30 coupled to a RF source power 32. Plasma isgenerated by applying the RF source power 32 to dissociate ions from theprocess gas, thereby forming a source of ions that are acceleratedtoward and implanted into the substrate 11. The implanted ions reactwith the atoms and molecules of the surface layer of the substrate 11.Thus, the ion implantation on corrosion resistant layer 15 is formed andis tightly bonded the substrate 11.

The ion implantation process may be performed under the followingconditions: The processing chamber 20 is evacuated to maintain apressure of about 1×10⁻⁴ Pa. The process gas supplied into theprocessing chamber 20 maintains a working atmosphere from about 0.1 Pato about 0.5 Pa. The RF source power 32 may be controlled from about 30kV to about 100 kV to form a beam of ions having an intensity of about 1milliampere (mA) to about 5 mA. The density of the ions implanted in theion implantation layer 13 may be from about 1×10¹⁶ ions per squarecentimeter (ions/cm²) to about 1×10¹⁸ ions/cm². The processing chamber20 may be maintained at a normal room temperature. The La metallurgicalbonds with the Al—O—N gradient layer by implantation, and forms theamorphous property. The structural characteristics of amorphous includesisotropic, no dislocation, and so on. Furthermore, the Al—O—N gradientlayer is a homogeneous amorphous film. And thus, the corrosionresistance of the substrate 11 can be improved.

EXAMPLES

Experimental examples of the present disclosure are described asfollowing.

Example 1

The vacuum sputtering equipment 20 used in example 1 is a mediumfrequency magnetron sputtering equipment (model No. SM-1100H)manufactured by South Innovative Vacuum Technology Co., Ltd.

The substrate is made of aluminum and aluminum alloys.

Plasma cleaning: Ar gas is fed into the vacuum chamber 21 at a flow rateof about 280 sccm. The aluminum or aluminum alloys substrate 11 isapplied with a negative bias voltage at −300 V. The plasma cleaning thealuminum or aluminum alloys substrate 11 takes about 9 min.

Sputtering of the aluminum layer 13: Ar gas is fed into the vacuumchamber 21 at a flow rate of about 100 sccm. The power of the aluminumtargets 23 is 2 kw and the aluminum and aluminum alloys substrate 11 isapplied with a negative bias voltage of −500 V. The depositing of thealuminum layer 13 takes 5 min.

Sputtering of the Al—O—N gradient layer: Argon, oxygen, and nitrogen aresimultaneously applied. The flux of the argon is about 100 sccm, theflux of the oxygen is about 10 sccm, and the flux of the nitrogen isabout 10 sccm. A bias voltage about −500 V is then applied to thesubstrate. Both the nitrogen and oxygen flow rates are each increasedabout 10 sccm about every 10 minutes and evaporate the aluminum targetat a power of about 5 kw. The depositing of the Al—O—N gradient layertakes a total of 30 min.

Ion implanting La ions comprises the following steps: the processingchamber is evacuated to maintain a pressure of about 1×10⁻⁴ Pa, theprocess gas maintains a working atmosphere of about 0.1 Pa in theprocessing chamber. The RF source power is at about 30 kV to form an ionbeam with an intensity of about 1 mA. The density of the ions implantedin the ion implantation layer is about 1×10¹⁶ ions/cm².

Example 2

The vacuum sputtering equipment 20 used in example 1 is a mediumfrequency magnetron sputtering equipment (model No. SM-1100H)manufactured by South Innovative Vacuum Technology Co., Ltd.

The substrate is made of aluminum and aluminum alloys.

Plasma cleaning: Ar gas is fed into the vacuum chamber 21 at a flow rateof about 480 sccm. The aluminum or aluminum alloy substrate 11 isapplied with a negative bias voltage at −300 V. The plasma cleaning thealuminum or aluminum alloy substrate 11 takes about 7 min.

Sputtering of the aluminum layer 13: Ar gas is fed into the vacuumchamber 21 at a flow rate of about 200 sccm. The power of the aluminumtargets 23 is 2 kw and the aluminum and aluminum alloys substrate 11 isapplied with a negative bias voltage of −400 V. The depositing of thealuminum layer 13 takes 7 min.

Sputtering of the Al—O—N gradient layer: Argon, oxygen, and nitrogen aresimultaneously applied, the flux of the argon is about 200 sccm, theflux of the oxygen being about 15 sccm and the flux of the nitrogen isabout 60 sccm; A bias voltage −300 V is then applied to the substrate.Both the nitrogen and oxygen flow rates are each increased 12 sccm aboutevery 15 minutes and evaporate the aluminum target at a power about 5kw. The depositing of the Al—O—N gradient layer takes a total of 60 min.

Ion implanting La ions comprises the following steps: The processingchamber is evacuated to maintain a pressure of about 1×10⁻⁴ Pa, theprocess gas maintains a working atmosphere of about 0.1 Pa in theprocessing chamber. The RF source power is at about 60 kV to form an ionbeam with an intensity of about 2 mA. The density of the ions implantedin the ion implantation layer is about 1×10¹⁷ ions/cm².

Example 3

The vacuum sputtering equipment 20 used in example 3 is the same inexample 1.

The substrate 11 is made of aluminum and aluminum alloys.

Plasma cleaning: Ar is fed into the vacuum chamber 21 at a flow rate ofabout 160 sccm. The aluminum or aluminum alloys substrate 11 is appliedwith a negative bias voltage at −400 V. The plasma cleaning the aluminumor aluminum alloy substrate 11 takes about 6 min.

Sputtering of the aluminum layer 13: Ar gas is fed into the vacuumchamber 21 at a flow rate of about 300 sccm. The power of the aluminumtargets 23 is 8 kw and the aluminum and aluminum alloys substrate 11 isapplied with a negative bias voltage of −300 V. The depositing of thealuminum layer 13 takes a total of about 10 min.

Sputtering of the Al—O—N gradient layer: simultaneously applying argon,oxygen, and nitrogen, the flux of the argon is about 300 sccm, the fluxof the oxygen being is 100 sccm, and the flux of the nitrogen is about20 sccm. A bias voltage about −150 V is then applied to the substrate;Both the nitrogen and oxygen flow rates are each increased about 20 sccmabout every 15 minutes and evaporate the aluminum target at a power ofabout 5 kw. The depositing of the Al—O—N gradient layer takes a total ofabout 90 min.

Ion implanting La ions comprises the following steps: The processingchamber is evacuated to maintain a pressure of about 1×10⁻⁴ Pa, and theprocess gas maintains a working atmosphere of about 0.1 Pa in theprocessing chamber. The RF source power is at about 100 kV to form anion beam with an intensity of about 5 mA. The density of the ionsimplanted in the ion implantation layer is about 1×10¹⁸ ions/cm².

It is to be understood, however, that even through numerouscharacteristics and advantages of the exemplary disclosure have been setforth in the foregoing description, together with details of the systemand function of the disclosure, the disclosure is illustrative only, andchanges may be made in detail, especially in matters of shape, size, andarrangement of parts within the principles of the disclosure to the fullextent indicated by the broad general meaning of the terms in which theappended claims are expressed.

What is claimed is:
 1. A housing, comprising: a substrate made ofaluminum or aluminum alloy; an aluminum layer formed on the aluminum oraluminum alloy; a corrosion resistant layer formed on the aluminumlayer; wherein the corrosion resistant layer is an Al—O—N gradient layerdoped with La ions, the atomic percentages of N and O in the Al—O—Ngradient layer gradually increase from the bottom of the layer near thealuminum or aluminum alloys substrate to the top of the layer away fromaluminum or aluminum alloys substrate.
 2. The housing as claimed inclaim 1, wherein the corrosion resistant layer has a thickness in arange of about 0.5 μm to about 2.0 μm.
 3. The housing as claimed inclaim 1, wherein the aluminum layer has a thickness in a range of about100 nm-about 300 nm.
 4. A method for surface treating aluminum oraluminum alloys, the method comprising the following steps of: providinga substrate made of aluminum or aluminum alloys; forming an aluminumlayer on the substrate by physical vapor deposition; forming a corrosionresistant layer formed on the aluminum layer, the corrosion resistantlayer is an Al—O—N gradient layer doped with La ions implanted by ionimplantation process, the atomic percentages of N and O in the Al—O—Ngradient layer gradually increase from the bottom of the layer near thealuminum or aluminum alloys substrate to the top of the layer away fromaluminum or aluminum alloys substrate.
 5. The method as claim in claim4, wherein the step of forming Al—O—N gradient layer comprises thefollowing steps: simultaneously applying argon, oxygen, and nitrogen,the flux of the argon being from about 100 sccm to about 300 sccm, theflux of the oxygen being from about 10 sccm to about 20 sccm and theflux of the nitrogen being from about 10 sccm to about 20 sccm; applyinga bias voltage to the substrate in a range of about −150 volt to about−500 volt; the flux of the nitrogen and oxygen flow rates are bothincreased approximately 10 sccm to 20 sccm at depositing interval ofabout every 10 minutes to about 15 minutes and evaporating the Al—O—Ngradient layer taking a total time of about 30 minutes to about 90minutes.
 6. The method as claim in claim 4, wherein, ion implanting Laions comprises the following steps: the processing chamber is evacuatedto maintain a vacuum degree of about 1×10⁻⁴ Pa, the process gasmaintains a working atmosphere from about 0.1 Pa to about 0.5 Pa in theprocessing chamber.
 7. The method as claim in claim 6, wherein the stepof ion implanting La ions further comprises supplying a RF source powerto dissociate the ions from the process gas.
 8. The method as claim inclaim 6, wherein the RF source power is controlled from about 30 toabout 100 kV to form a beam of the ions with an intensity from about 1to about 5 mA.
 9. The method as claimed in claim 6, wherein the densityof the ions implanted in the ion implantation layer is in a range ofabout 1×10¹⁶ ions/cm² to about 1×10¹⁸ ions/cm².
 10. The method asclaimed in claim 4, wherein the step of forming the aluminum layer isachieved in the following condition: using argon gas as sputtering gas,the flux of the argon being from about 100 sccm to about 300 sccm;magnetron sputtering the temperature of aluminum layer is in a range ofabout 180° C. to about 250° C., the power of the aluminum targets is ina range of about 2 kw to about 8 kw, the substrate is applied with anegative bias voltage is in a range of about −300 V to about −500 V,vacuum sputtering the aluminum layer takes about 5 min to about 10 min.11. The method as claim in claim 4, wherein the method further comprisespolishing and ultrasonically cleaning the substrate before forming thealuminum layer.